Avaliação da patogenia de estirpes de Salmonella enterica SUBSP. enterica sorotipo Gallinarum biovar Gallinarum com os genes responsáveis pela expressão de flagelo ativos

• Autor(a) principal: Lopes, Priscila Diniz [UNESP]
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/108642
• topic: Ave - Doenças; Salmonella gallinarum; Bacterias patogenicas; Genes; Patogenicidade; Genetics

The fowl typhoid is a systemic disease of chickens caused by Salmonella enterica subsp. enterica serovar Gallinarum biovar Gallinarum (SG), a microorganism that does not produce flagella. It is suggested that due to the absence of flagella SG is poorly recognized by the bird immune system. As a result, just a mild inflammation is induced in the gut mucosa, favoring the development of a severe systemic infection. In order to investigate this hypothesis, in a previous study, a mutant of SG capable of producing flagella (SG Fla+) was constructed. This mutant was able to trigger mRNA pro-inflammatory cytokines e chemokines in cultured cells and was less pathogenic to birds than the wild type strain. However, it was noticed that SG Fla+ trends to stop flagella production after culturing two or more times on solid medium, becoming non-flagelated (SG Fla-). The present study aimed at comparing the pathogenicity of SG Fla+, SG Fla- and SG to birds. In the first experiment, mortality rates caused by strains and fecal excretion were evaluated. In the second assay, the ability of strains in colonizing the ceca and invading liver and spleen were compared. In addition to this, the presence and intensity of macroscopic and microscopic lesions in organs were evaluated. When inoculated in the lower amount (106 CFU) SG Fla+ provoked less mortality than the non-flagellate strains. The results of fecal excretion indicate that SG Fla+ was more excreted than the other strains. It was observed that SG and SG Fla- were recovered from cecal contents in higher amounts than SG Fla+. SG Fla- and SG were isolated earlier and in higher amounts from liver and spleen. In the liver degeneration, congestion, changes in color (greenish-yellow to greenish), lymphoid reactivity and multifocal areas of necrosis were noticed. Spleen was enlarged and congested; foci of necrosis in the white pulp and lymphoid depletion were also ...